Operating Cable Modems in a Low Power Mode

1. An apparatus, comprising: a receiver configured to receive chunks of data on a downstream channel from a cable modem termination system, the receiver being further configured to enter a low power state in which the chunks of data cannot be received; and wake up circuitry configured to monitor data in the downstream channel for a wake up signal when the receiver is in the low power state, where the wake up signal is inserted into the chunks of data and portions of the chunks of data are overwritten.

2. The apparatus of claim 1 , wherein the wake up circuitry is further configured to cause the receiver to exit the low power state when the wake up signal is received.

3. The apparatus of claim 1 , wherein the wake up circuitry is further configured to identify the wake up signal when an address in the data in the downstream channel matches a corresponding address of the apparatus.

4. The apparatus of claim 1 , wherein the wake up circuitry includes one of an amplitude modulation receiver, a frequency modulation receiver, and a code division modulation receiver.

5. The apparatus of claim 1 , further comprising: a transmitter configured to transmit chunks of data to the cable modem termination system, the transmitter being further configured to enter a low power mode.

6. The apparatus of claim 5 , wherein the wake up circuitry is further configured to cause the transmitter to exit the low power state when the wake up signal is received.

7. The apparatus of claim 1 , further comprising: interface circuitry configured to transfer data from the receiver to a telephone device that is connected to the apparatus.

8. A cable modem termination system, comprising: a transmitter for sending chunks of data to one or more cable modems on a downstream channel; and signaling circuitry configured to insert a wake up message into the chunks of data on the downstream channel for causing a device to exit a low power mode, where the signaling circuitry is further configured to overwrite portions of the chunks of data.

9. The cable modem termination system of claim 8 , wherein the signaling circuitry includes one of an amplitude modulator, a frequency modulator, and a code division modulator to modulate the wake up message.

10. A method of low power operation in a cable modem system, comprising: deciding to enter a low power state; removing power from at least one of a transmitter and a receiver; monitoring a downstream communication channel for a wake up message, where the wake up message is inserted into chunks of data on the downstream communication channel and portions of the chunks of data are overwritten; and supplying power to the at least one of the transmitter and the receiver upon reception of the wake up message.

11. The method of claim 10 , further comprising: sending a sleep message indicating the decision to enter the low power state; and receiving an acknowledgement of the sleep message.

12. The method of claim 11 , wherein the removing occurs after the receiving.

13. The method of claim 10 , wherein the removing includes removing power from both the transmitter and the receiver.

14. The method of claim 10 , wherein the monitoring includes determining whether a specific identifier is present in data on the downstream communication channel.

15. The method of claim 10 , wherein the supplying includes supplying power to both the transmitter and the receiver.

16. The method of claim 10 , further comprising: sending an awake message indicating an exit from the low power state; and receiving an acknowledgement of the awake message.

17. A system, comprising: a multimedia terminal adapter including: a receiver configured to receive chunks of data on a downstream channel and further configured to be placed into a low power mode, and wake up circuitry configured to monitor data on the downstream channel for a wake up signal when the receiver is in the low power mode; and a cable modem termination system operatively connected to the multimedia terminal adapter by the downstream channel, the cable modem termination system including: a transmitting portion configured to send the chunks of data to the multimedia terminal adapter, and signaling circuitry configured to insert the wake up signal into the chunks of data for causing the multimedia terminal adapter to exit the low power mode, where the signaling circuitry is further configured to overwrite portions of the chunks of data.

18. The system of claim 17 , wherein the multimedia terminal adapter further includes: a transmitter configured to transmit chunks of data to the cable modem termination system, the transmitter being further configured to be placed into the low power mode.

19. The system of claim 18 , further comprising: a telephone device operatively coupled to the receiver and the transmitter, the telephone device being configured to send and receive voice data.

20. The system of claim 17 , wherein the wake up circuitry and the signaling circuitry are respectively configured to demodulate the wake up signal and to modulate the wake up signal using a common modulation scheme.

21. The system of claim 20 , wherein the common modulation scheme differs from a transmission format used by the transmitting portion to send the chunks of data to the multimedia terminal adapter.

22. A multimedia terminal adapter, comprising: a receiver configured to receive chunks of data on a downstream channel from a cable modem termination system; control circuitry configured to selectively remove power from the receiver, and wake up circuitry configured to monitor the chunks of data on the downstream channel for a wake up signal when the power has been removed from the receiver, where the wake up signal is inserted into the chunks of data and portions of the chunks of data are overwritten.

23. The multimedia terminal adapter of claim 22 , wherein the wake up circuitry is further configured to cause the control circuitry to restore power to the receiver when the wake up signal is received.

24. The multimedia terminal adapter of claim 22 , wherein the wake up circuitry is further configured to identify the wake up signal when an address in the chunks of data matches a corresponding address of the multimedia terminal adapter.

25. An apparatus, comprising: means for receiving chunks of data from a cable modem termination system; means for selectively removing power from the means for receiving, and means for monitoring the chunks of data for a wake up signal, where the wake up signal is inserted into the chunks of data and portions of the chunks of data are overwritten.